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Mammals may have originated much earlier than thought?

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Three Jurassic euharamiyidan mammals left/Zhao Chuang

From ScienceDaily:

Paleontologists have described three new small squirrel-like species that place a poorly understood Mesozoic group of animals firmly in the mammal family tree. The study, led by scientists at the American Museum of Natural History and the Chinese Academy of Sciences, supports the idea that mammals — an extremely diverse group that includes egg-laying monotremes such as the platypus, marsupials such as the opossum, and placentals like humans and whales — originated at least 208 million years ago in the late Triassic, much earlier than some previous research suggests.

“For decades, scientists have been debating whether the extinct group, called Haramiyida, belongs within or outside of Mammalia,” said co-author Jin Meng, a curator in the Museum’s Division of Paleontology. “Previously, everything we knew about these animals was based on fragmented jaws and isolated teeth. But the new specimens we discovered are extremely well preserved. And based on these fossils, we now have a good idea of what these animals really looked like, which confirms that they are, indeed, mammals.” More.

See also: Mites have parasitized ants for 45 mya longer than thought (Living member species of family parasitize ants today.)

From Live Science:

Judging from their slender builds, long tails, hands and feet adapted for grasping and climbing, and enlarged incisor teeth, these animals would have been tree-dwellers that looked similar to squirrels. However, “don’t confuse these new animals with any living species,” Meng said. Any similarities between these creatures and squirrels are due to convergent evolution, just as fish and dolphins both have streamlined bodies to better swim in the water but are only distantly related.

Apparently, this line died out. That said,

Many scientists had suggested that mammals originated in the Middle Jurassic, which ranged from 174 million to 164 million years ago. “Haramiyids are one of the oldest group of mammals, if not the oldest,” Meng said.

Here’s the abstract:

The phylogeny of Allotheria, including Multituberculata and Haramiyida, remains unsolved and has generated contentious views on the origin and earliest evolution of mammals. Here we report three new species of a new clade, Euharamiyida, based on six well-preserved fossils from the Jurassic period of China. These fossils reveal many craniodental and postcranial features of euharamiyidans and clarify several ambiguous structures that are currently the topic of debate. Our phylogenetic analyses recognize Euharamiyida as the sister group of Multituberculata, and place Allotheria within the Mammalia. The phylogeny suggests that allotherian mammals evolved from a Late Triassic (approximately 208 million years ago) Haramiyavia-like ancestor and diversified into euharamiyidans and multituberculates with a cosmopolitan distribution, implying homologous acquisition of many craniodental and postcranial features in the two groups. Our findings also favour a Late Triassic origin of mammals in Laurasia and two independent detachment events of the middle ear bones during mammalian evolution. (paywall)

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4 Replies to “Mammals may have originated much earlier than thought?

  1. 1
    HeKS says:

    “For decades, scientists have been debating whether the extinct group, called Haramiyida, belongs within or outside of Mammalia,” said co-author Jin Meng, a curator in the Museum’s Division of Paleontology. “Previously, everything we knew about these animals was based on fragmented jaws and isolated teeth. But the new specimens we discovered are extremely well preserved. And based on these fossils, we now have a good idea of what these animals really looked like, which confirms that they are, indeed, mammals.”

    I got a real kick out of that paragraph. When it comes to Triassic Squirrels, jaw fragments and isolated teeth aren’t much to go on and scientists will spend decades patiently debating whether or not they might fall into the Mammalia class of animals. When it comes to alleged human ancestors, jaw fragments and teeth apparently offer enough information to tell us not only the entire shape of the creature’s head, but how many hair it, whether it was bipedal, how long its arms were, where it likely spent most of its time, how intelligent it was, and what type of culture it may have lived in, which might have been none at all.

  2. 2
    HeKS says:

    “how many hair it” = “how much hair it had” (obviously)

  3. 3
    lifepsy says:

    Well the “reptile-mammal” jaw-earbone transition was already on shaky ground, but with fully mammalian earbone morphology showing up in the middle of that sequence, it looks like it’s now been officially demoted to anochronistic ambiguity like so many other so-called fossil “transitions”…

    Maybe evolutionists will start openly admitting that these alleged transitional sequences tend to *not* be in stratigraphic order instead of shrouding that inconvenient fact in a cloud of smoke. Probably wishful thinking…

  4. 4
    Andre says:

    We are getting closer and closer to pulling a rabbit from the Cambrian…….. Cheers Charles thanks for misleading the ignorant for 200 years! Don’t let the door hit you on the way out!

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